This application is for the acquisition of a 200-MHz, wide-bore, multi-nuclear, NMR spectrometer, accompanying data system, and accessories. The recent advances in instrument design and data analysis techniques represented by this instrument will allow the performance of experiments that are not feasible with lower-field, older instruments such as the XL-100 FT. Thirteen principal investigators, conducting research under NIH sponsorship through eighteen grants, would use the NMR spectrometer on a shared basis. A senior NMR spectroscopist for consultation and data interpretation and an instrument operator would be available to assist these scientists in obtaining the maximum useful information from the instrument. The 200-MHz would be a powerful tool in such diverse reseach as stable-isotope labeling studies to elucidate biosynthetic pathways of antibiotics and other natural products; studies of enzyme-substrate and drug-DNA interactions; identification of metabolites and biochemical intermediates; and characterization of newly synthesized compounds of medicinal potential. These research programs would greatly benefit from the sensitivity, dispersion, and versatility of the requested instrument. Instrument supervision, operation, maintenance, and time allocation will be provided by the existing organizational structure within the Bio-Organic Chemistry Laboratory's NMR service facility. Advisory oversight of the allocation and use of the new instrument will be provided by the existing Biomedical Research Support Committee. Utilization of these proven, established administrative bodies will assure satisfactory and orderly support for the different research projects requiring NMR services.